title: [In vitro evaluation of MR thermometry in the implementation of laser-induced thermotherapy].
abstract: OBJECTIVE
  To optimize the MR sequences parameter for monitoring hyperthermic effects in the tissue during laser induced thermotherapy (LITT).
  
  
  METHODS
  Experimental studies were performed for the evaluation of MR-thermometry using a contrast-agent-water solution and a pig-liver. A T1-weighted TurboFLASH sequence and a FLASH-2D sequence were used. The TurboFLASH sequence was used with various T1 settings (between 100 and 1250 ms). MR findings were correlated with temperature measurements using a fluoride optical temperature measuring system in a distance of 1, 2, and 5 cm from the laser applicator.
  
  
  RESULTS
  Using the contrast-agent-water solution demonstrated the temperature sensitivity of both sequences. In vitro evaluations using pig liver demonstrated a near linear increase of signal versus increasing tissue temperatures in a distance of 1 cm to the tip of the laser applicator. Optimal visualization of the temperature effects was obtained using a T1 between 100 ms and 400 ms. Using the FLASH-2D sequence a signal loss was documented at a TR of 110 ms.
  
  
  CONCLUSIONS
  MR-thermometry using sequentially TurboFLASH and FLASH-2D sequences allowed a non-invasive monitoring of the laser induced temperature changes.
authors.affiliation: Strahlenklinik und Poliklinik, Virchow-Klinikum, Humboldt-Universität zu Berlin.
authors.forename: T J
authors.initials: TJ
authors.lastname: Vogl
authors.forename: M G
authors.initials: MG
authors.lastname: Mack
authors.forename: H H
authors.initials: HH
authors.lastname: Hirsch
authors.forename: P
authors.initials: P
authors.lastname: Müller
authors.forename: N
authors.initials: N
authors.lastname: Weinhold
authors.forename: P
authors.initials: P
authors.lastname: Wust
authors.forename: C
authors.initials: C
authors.lastname: Philipp
authors.forename: A
authors.initials: A
authors.lastname: Roggan
authors.forename: R
authors.initials: R
authors.lastname: Felix
mesh_terms: D000818:Animals; D001831:Body Temperature; D003287:Contrast Media; D006979:Hyperthermia, Induced; D066298:In Vitro Techniques; D017075:Laser Coagulation; D053685:Laser Therapy; D007834:Lasers; D008099:Liver; D008113:Liver Neoplasms / Q000601:surgery / Q000628:therapy; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008991:Monitoring, Physiologic; D013552:Swine; D013821:Thermometers; D013997:Time Factors
chemical_list: D003287:Contrast Media
vernacular_title: In-vitro-Evaluierung der MR-Thermometrie zum Einsatz der laserinduzierten Thermotherapie.